In Safari 5.1.7, no favicons of any type appear there now. I never looked during the time that the FTM favicon had disappeared so I can't confirm your observation.

Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365